Divisionalized foldable display ultra-thin glass cover window using glass-fabric reinforced siloxane hybrimer film

Abstract

With the recent advent of foldable displays, they are attracting attention due to their unique user experience. Therefore, as display technologies diversify, it becomes increasingly urgent to develop innovative materials and components for these sophisticated systems. In particular, the key component is the cover window located above the display panel, which protects the fragile OLED or LCD from external shock. In the case of foldable displays, the standards for these cover windows become more stringent. Not only must it provide good surface durability and excellent optical properties, but it must also be highly flexible to cope with the mechanical stresses associated with the folding function. In the case of currently commercialized cover windows, the folding function is reduced due to complex processes and unnecessary increase in thickness due to PSA. Therefore, the industry is conducting research to etch the UTG in the folding area using a laser, but its feasibility is uncertain due to the difficulty and cost of the process. In this paper, a UTG/glass-fabric reinforced plastic/hard coating composite film was developed using glass-fabric reinforced siloxane material. In order to improve the foldability, the glass-fabric in the folding area was removed in advance to consist only of siloxane hybrimer, and the surface hardness was improved through hard coating layer. As a result, a composite film was developed that can be folded 100,000 times at a folding radius of $1.5 mm$ and has high hardness and impact resistance. In addition, through mechanical/extreme environment stability tests, it was confirmed that a foldable device cover window application is feasible.